When in EW, split the options for the lvl based ones to 1-50, 51-70, 71-80, 81-90. As this way you arent removing dungeons from the pool of options.

I also would like a way to promote doing these in sync. As now most trials are just quickly beaten in unsync, just to get rid of them. And for this i would suggest the following:
Upon completing any of the expert chalenges in sync, you are rewarded a token to move a sticker (and you can stack up 9 of these to allow a nice buffer). These can still only be used when the journal is at 7/9 or lower 9 and directly after a shuffle). But this should significantly boost the chances on 3 lines.

And with it, add a Journal Roulette. Instead of just focussing on a dungeon, trial or raid, it simply queues you for any of these.
It will not choose any of the lvl based options, therefor prioritizing on the expert content. Upon having nothing remaining in the journal (9/9), this roulette is locked.
If the additional sync idea would be applied, this roulette remains available to obtain thoes tokens (and after 9 it locks again)